HOLLYWOOD—“Grey's Anatomy” fans will now have to prepare to say goodbye to a beloved character.

Reports of Sandra Oh's departure from the hit medical drama confirm the cast shake up, and the critically acclaimed actress will leave at the end of the show's tenth season. Oh has portrayed “Grey's” character Dr. Cristina Yang since the television series first premiered in 2005. In May 2012, the actress signed a two-year deal for the show, committing her through the tenth season. Oh will leave the program in 2014.

Sandra Oh as Cristina Yang

"It’s been a great privilege to play the character of Cristina Yang on 'GA' and I am both sad and excited to see where this, her final season will take her,” said Oh in a statement. “It was an emotional and deeply creative decision for me and I feel fully supported by Shonda and the writers. It's so rare in an actor’s life to be able to explore and grow a character so fully, so completely. I am profoundly grateful to everyone at 'GA' for the opportunity. I’m excited to celebrate and cherish every moment of my final season on 'GA' with the fans who have made it all possible."

Fellow original cast members Patrick Dempsey, Ellen Pompeo, Justin Chambers, Chandra Wilson and James Pickens Jr. also signed a similar deal in 2012, and though Oh's future in the show is certain, her co-stars have yet to formally finalize a contract after the end of season 10. Numerous series regulars and original cast members have left the show since its premiere, including Katherine Heigl, T.R. Knight and Isaiah Washington.

The loss of Oh, however, is a significant blow to the show's foundation. Her character, Cristina Yang, is considered essential to the heart of the series, and as best friend of “Grey's” titular protagonist, Yang's friendship with Meredith (Ellen Pompeo) is deemed by critics and audiences alike as central to the show's core. Oh has been nominated five times for a Primetime Emmy, and she won a Golden Globe and Screen Actors Guild Award in 2006 for her portrayal of the ambitious, intelligent and aggressive doctor.

"One of the best days of my life as a writer happened the day Sandra Oh walked in my door to audition and forever changed the course of 'Grey's Anatomy' with her brilliant, nuanced portrayal of Cristina Yang," Shonda Rhimes, the series creator, said in a statement. "Over the past ten seasons, I have been made better by Sandra's trust, faith and friendship and I can't quantify how grateful I am for her collaboration on a character we both love so deeply. This year is going to be bittersweet for us -- we're both going to savor every moment of Cristina Yang and then we're going to give her the exit she deserves. And when Sandra walks out of my door, 'Grey's Anatomy' will be once again be forever changed."

ABC has publicly reasserted that it intends to keep the show on for as long as possible, and the network intends to retain as much of the original cast as it can throughout the show's lifetime.